Davis has two years left on a six-year deal worth $42.7 million. But he apparently isn’t happy with the contract he signed before the 2010 season. It also included a $10 million signing bonus. CSNBayArea.com reports that with an average salary of $7.35 million a year, he is third among tight ends behind Rob Gronkowski of the Patriots at $8 million and Jason Witten of the Cowboys at $7.4 million.

You can’t argue with his 2013 production: 52 receptions for 850 yards and 13 touchdowns.

Coach Jim Harbaugh dismissed Davis’ absence: “As you know, the workouts are voluntary. That would be the reason.”

Davis, however, gets a $200,000 annual workout bonus. He’s willing to give that up for now. Mandatory minicamp is June 17-19 and if he’s not there, he can be fined up to $60,000.

Meeting Davis halfway may not be easy for the 49ers, who are a mere $1.73 million under the salary cap. They’ll get another $6.6 million in cap space next week, the website reports, when Carlos Rogers’ contract is off the books.

Whatever is done, it has to be with quarterback Colin Kaepernick in mind. His rookie deal ends after 2014 and Kaepernick reportedly wants upward of $18 million.

If he backs up the success he’s already had the way Harbaugh predicts he will, Kaepernick could well be entitled to that kind of windfall.

“He just has the look and feel that he’s going to break out, more so than he already has,” Harbaugh said. “I’m really excited about everything about his game right now. He added: “Athletically, he looks bionic. We all remember the ‘Six Million-Dollar Man.’ That’s what he looks like to me. He’s very gifted and he always has been.”

Kaepernick has to be paid, as does receiver Michael Crabtree and guard Mike Iupati. Aldon Smith’s salary goes up to $9.754 million in 2015.